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Fourier series calculator piecewise - The Fourier Series With this application you can see how a sum of enough sinusoidal functions may lead to a

3.4: Sine and Cosine Series. In the last two examples (f(x) = | x | and f(x) = x on [ − π

About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features Press Copyright Contact us Creators ...May 30, 2016 · The problem formulation is causing me difficulties here. Usually, when finding the Fourier series of a periodic function, the author states "compute (or find) the Fourier series of the given function". Fourier Series Calculator is a Fourier Series on line utility, simply enter your function if piecewise, introduces each of the parts and calculates the Fourier coefficients may also represent up to 20 coefficients. Derivative numerical and analytical calculator.The Fourier series for an even function with period 2L 2 L is thus given by the Fourier cosine series. f(x) = a0 2 +∑n=1∞ an cos nπx L, f(x) even. (9.4.2) (9.4.2) f ( x) = a 0 2 + ∑ n = 1 ∞ a n cos n π x L, f ( x) even. Second, if f(x) f ( x) is odd, then.an infinite or semi-infinite spatial domain. Several new concepts such as the "Fourier integral representation" and "Fourier transform" of a function are introduced as an extension of the Fourier series representation to an infinite domain. We consider the heat equation ∂u ∂t = k ∂2u ∂x2, −∞ < x < ∞ (1) with the initial ...I tried to find the series of this function, but when I plot up to 50 terms with Wolfram, it doesn't resemble the function so I guess I made a mistake finding the Fourier series. This is what I did: The length of the interval is L = 2π L = 2 π. I calculated the coefficients as follows. a0 an bn = 1 L ∫2π 0 f(x)dx = 1 L(∫π 0 sin(x)dx ...On-Line Fourier Series Calculator is an interactive app to calculate Fourier Series coefficients (Up to 10000 elements) for user-defined piecewise functions up to 5 pieces, for example. \( f(x) = …Apr 17, 2021 · 1. Here's one way to calculate the Fourier transform: The distributional derivative of f f satisfies the equation. f′(x) = −f(x) +e1δ(x + 1) −e−1δ(x − 1). f ′ ( x) = − f ( x) + e 1 δ ( x + 1) − e − 1 δ ( x − 1). Taking the Fourier transform of both sides gives. jωf^(ω) = −f^(ω) +e1ejω −e−1e−jω j ω f ^ ( ω ... S is the function the series is approximating. M is the range on which S is assumed to be periodic. N is the number of terms in the series. Note that large values of N may lead to less accurate series because integrals in desmos can be a bit jank. Oh! I did this a while back too :) or maybe I didn't make this.5.3.2 Integration of Fourier series We can now establish a useful property of Fourier series, namely that term-wise integration is permissible. Theorem 5.6: The Fourier series of a period 2 π piecewise continuous function can be integrated term-by-term, over any finite interval. Proof: Let f p be a period 2 π piecewise continuous function ...If it wasn't a piecewise I would use the trick of subbing in a negative x but when there are two parts to it I don't . Stack Exchange Network. Stack Exchange network consists of 183 Q&A communities including Stack Overflow, ... fourier-analysis; graphing-functions. Featured on Meta Alpha test for short survey in banner ad slots starting on week ...1. What is the Fourier series for 1 + sin2 t? This function is periodic (of period 2ˇ), so it has a unique expression as a Fourier series. It’s easy to nd using a trig identity. By the double angle formula, cos(2t) = 1 2sin2 t, so 1 + sin2 t= 3 2 1 2 cos(2t): The right hand side is a Fourier series; it happens to have only nitely many terms. 2.Mathematica has four default commands to calculate Fourier series: where Ak = √a2k + b2k and φk = arctan(bk / ak), ϕk = arctan(ak / bk). In general, a square integrable function f ∈ 𝔏² on the interval [𝑎, b] of length b−𝑎 ( b >𝑎) can be expanded into the Fourier series.15.1 Convergence of Fourier Series † What conditions do we need to impose on f to ensure that the Fourier Series converges to f. † We consider piecewise continuous functions: Theorem 1 Let f and f0 be piecewise continuous functions on [¡L;L] and let f be periodic with period 2L, then f has a Fourier Series f(x) » a0 2 + P1 n=1 an cos ¡ n ...Goffman, Casper. Everywhere convergence of Fourier series. Indiana Univ. Math. J. 20 (1970/71), 107-112. From the Math Review: The author obtains results on the everywhere convergence of the Fourier series of regulated functions that satisfy certain generalized conditions of bounded variation. (Regulated functions are those for which right and left limits exist at every point.)Fourier Series 3 where an = 2 L ∫L 0 1 2 [f(x)+f(x) cos (nˇxL) dx = 1 L L L f(x)cos (nˇxL) dx bn = 2 L ∫L 0 1 2 [f(x) f(x) sin (nˇxL) dx = 1 L L L f(x)sin (nˇxL) dx: 14.3 Half-Range Expansions If we are given a function f(x) on an interval [0;L] and we want to represent f by a Fourier Series we have two choices - a Cosine Series or a Sine Series.Free functions and line calculator - analyze and graph line equations and functions step-by-step ... Integrals Integral Applications Integral Approximation Series ODE Multivariable Calculus Laplace Transform Taylor/Maclaurin Series Fourier Series Fourier Transform. Functions. ... Piecewise Functions; Continuity; Discontinuity; Values Table ...Therefore, the Fourier transform of the rectangular function is. F[∏( t τ)] = τ⋅ sinc( ωτ 2) F [ ∏ ( t τ)] = τ ⋅ s i n c ( ω τ 2) Or, it can also be represented as, ∏( t τ) FT ↔ τ⋅ sinc(ωτ 2) ∏ ( t τ) ↔ F T τ ⋅ s i n c ( ω τ 2) Magnitude and phase spectrum of Fourier transform of the rectangular function.High order and sparse layers in pytorch. Lagrange Polynomial, Piecewise Lagrange Polynomial, Piecewise Discontinuous Lagrange Polynomial (Chebyshev nodes) and Fourier Series layers of arbitrary order. Piecewise implementations could be thought of as a 1d grid (for each neuron) where each grid element is Lagrange polynomial. Both full connected a…May 28, 2017 · 3) Find the fourier series of the function. f(x) ={1, 0, if |x| < 1 if 1 ≤|x| < 2 f ( x) = { 1, if | x | < 1 0, if 1 ≤ | x | < 2. Added is the solution: In the first step I dont get why they use f(x) = 0 f ( x) = 0 if −2 ≤ x ≤ −1 − 2 ≤ x ≤ − 1 and f(x) = 0 f ( x) = 0 if 1 ≤ x ≤ 2 1 ≤ x ≤ 2. Why smaller/bigger or ... A function f : [a,b] → R is called piecewise continuous iff holds, (a) [a,b] can be partitioned in a finite number of sub-intervals such that f is continuous on the interior of these sub-intervals. (b) f has finite limits at the endpoints of all sub-intervals. The Fourier Theorem: Piecewise continuous case. Theorem (Fourier Series)Fourier Series--Triangle Wave. Consider a symmetric triangle wave of period . Since the function is odd , Now consider the asymmetric triangle wave pinned an -distance which is ( )th of the distance . The displacement as a function of is then. Taking gives the same Fourier series as before.Compute answers using Wolfram's breakthrough technology & knowledgebase, relied on by millions of students & professionals. For math, science, nutrition, history ...The Fourier transform can be viewed as the limit of the Fourier series of a function with the period approaches to infinity, so the limits of integration change from one period to $(-\infty,\infty)$. In a classical approach it would not be possible to use the Fourier transform for a periodic function which cannot be in $\mathbb{L}_1(-\infty ...Mathematica has four default commands to calculate Fourier series: where Ak = √a2k + b2k and φk = arctan(bk / ak), ϕk = arctan(ak / bk). In general, a square integrable function f ∈ 𝔏² on the interval [𝑎, b] of length b−𝑎 ( b >𝑎) can be expanded into the Fourier series. What will be the new Fourier series coefficients when we shift and scale a periodic signal? Scaling alone will only affect fundamental frequency. But how to calculate new coefficients of shifted and scaled version. I tried searching, but couldn't find an answer where both properties are used. Please help. fourier-series; Share. Improve this …Explore math with our beautiful, free online graphing calculator. Graph functions, plot points, visualize algebraic equations, add sliders, animate graphs, and more.Fourier Integral Fourier Series to Fourier Integral Theorem If fis absolutely integrable Z 1 1 jf(x)jdx<1 ; and f;f0are piecewise continuous on every nite intreval, then Fourier integral of fconverges to f(x) at a point of continuity and converges to f(x+0)+ f(x 0) 2 at a point of discontinuity.Calculate the sum of an arithmetic sequence with the formula (n/2)(2a + (n-1)d). The sum is represented by the Greek letter sigma, while the variable a is the first value of the sequence, d is the difference between values in the sequence, ...To calculate Laplace transform method to convert function of a real variable to a complex one before fourier transform, use our inverse laplace transform calculator with steps. Fourier transform of odd and even functions: The fourier coefficients a 0, a n, or b n may get to be zero after integration in certain Fourier transform problems. When dealing with Fourier cosine and sine series, you are actually extending a non-periodic function onto a periodic even or odd domain. Hence the effective period is actually twice as large instead, that is to say, you are actually working with the interval -4 < x < 4 here as the basic unit. Jan 2, 2015. #3.General Fourier series If f(x) is 2p-periodic and piecewise smooth, then fˆ(x) = f(px/π) has period 2p p/π = 2π, and is also piecewise smooth. It follows that fˆ(x) has a Fourier series: fˆ(x+) + fˆ(x−) 2 = a 0 + X∞ n=1 (a n cos(nx) + b n sin(nx)). Since f(x) = fˆ(πx/p), we find thatf also has a Fourier series: f(x+) + f(x−) 2 ...x greater than Pi number. -pi/2 <= x <= pi/2. x less than or equal to Pi number in half, but not strictly greater than Pi in half. true. means "otherwise". First, set the function: Piecewise-defined. Piecewise-continuous. The above examples also contain:The Fourier transform is an integral transform widely used in physics and engineering. They are widely used in signal analysis and are well-equipped to solve certain partial differential equations. ... or the unit pulse, is defined as a piecewise function that equals 1 if < <, and 0 everywhere else. As such, we can evaluate the integral over ...(9) The Fourier series is... Consider a string of length 2L plucked at the right end and fixed at the left. The functional form of this configuration is f(x)=x/(2L).We shall shortly state three Fourier series expansions. They are applicable to func-tions that are piecewise continuous with piecewise continuous first derivative. In applications, most functions satisfy these regularity requirements. We start with the definition of “piece-wise continuous”. More examples on Fourier series expansions of non-periodic functions.Number Series. Power Series. Taylor / Laurent / Puiseux Series. Math24.pro [email protected] Free Fourier Series calculator - Find the Fourier series of functions Online.Fourier Series. This TI-83 Plus and TI-84 Plus Fourier series program calculates the coefficients of the sine and cosine terms of the Fourier series for an arbitrary function over the interval [-pi,pi]. The result is a series of sine/cosine waves that when added closely resemble the original function.A Fourier series is a way of representing a periodic function as a (possibly infinite) sum of sine and cosine functions. It is analogous to a Taylor series, which represents functions as possibly infinite sums of monomial terms. For functions that are not periodic, the Fourier series is replaced by the Fourier transform. For functions of two variables that are periodic in both variables, the ...To calculate Laplace transform method to convert function of a real variable to a complex one before fourier transform, use our inverse laplace transform calculator with steps. Fourier transform of odd and even functions: The fourier coefficients a 0, a n, or b n may get to be zero after integration in certain Fourier transform problems.According to the convolution property, the Fourier series of the convolution of two functions 𝑥 1 (𝑡) and 𝑥 2 (𝑡) in time domain is equal to the multiplication of their Fourier series coefficients in frequency domain. If 𝑥 1 (𝑡) and 𝑥 2 (𝑡) are two periodic functions with time period T and with Fourier series ...Free functions and line calculator - analyze and graph line equations and functions step-by-step ... Integrals Integral Applications Integral Approximation Series ODE Multivariable Calculus Laplace Transform Taylor/Maclaurin Series Fourier Series Fourier Transform. Functions. ... Piecewise Functions; Continuity; Discontinuity; Values Table ...Find, customize, share, and embed free Wolfram|Alpha Widgets in dozens of categories: weather, calculators, math, science, finance, health & nutrition, astronomy ...FOURIER SERIES Let fðxÞ be defined in the interval ð#L;LÞ and outside of this interval by fðx þ 2LÞ¼fðxÞ, i.e., fðxÞ is 2L-periodic. It is through this avenue that a new function on an infinite set of real numbers is created from the image on ð#L;LÞ. The Fourier series or Fourier expansion corresponding to fðxÞ is given by a 0 ...Explore math with our beautiful, free online graphing calculator. Graph functions, plot points, visualize algebraic equations, add sliders, animate graphs, and more. Fourier Series Sum. Save Copy. Log InorSign Up. Start with period... 1. P = 3. 2. Enter expressions for coefficients here: 3. a 0 = 1. 4. a n = 0. 5. The notation "{when: value, when: value, …TOPICS. Algebra Applied Mathematics Calculus and Analysis Discrete Mathematics Foundations of Mathematics Geometry History and Terminology Number Theory Probability and Statistics Recreational Mathematics Topology Alphabetical Index New in MathWorld1. Find the Fourier series of the functionf defined by f(x)= −1if−π<x<0, 1if0<x<π. and f has period 2π. What does the Fourier series converge to at x =0? Answer: f(x) ∼ 4 π ∞ n=0 sin(2n+1)x (2n+1). The series converges to 0. So, in order to make the Fourier series converge to f(x) for all x we must define f(0) = 0. 2. What is the ...Fourier Series Roughly speaking, a Fourier series expansion for a function is a representation of ... We start with the definition of "piece-wise continuous". A function f(x) is said to be piecewise continuous if it is continuous except for isolated jump discontinuities. In the example below, f(x) is continuous except for jumpfourier-series-calculator. pt. Postagens de blog relacionadas ao Symbolab. Advanced Math Solutions – Ordinary Differential Equations CalculatorViewed 3k times. 2. Obtain the fourier series on the interval: [ − π, π] of the function: f ( x) = { − π x if − π ≤ x ≤ 0 x 2 if , 0 < x ≤ π. Solution given by book: S ( x) = 5 π 2 12 + ∑ n = 1 ∞ [ 3 ( − 1) n − 1 n 2 cos n x + 2 ( − 1) n − 1 n 3 π sin n x] basically i'm stuck because I can't get my answer to match ...Fourier Series is a way of approximating arbitrary function (f (x)) as an infinite sum of sines and cosines of increasingly high frequency that provide an orthogonal basis for the space of solution functions. The sine and cosine functions present as eigenfunctions of the heat equation. The specific frequencies provided present as eigenvalues ...http://adampanagos.orgJoin the YouTube channel for membership perks:https://www.youtube.com/channel/UCvpWRQzhm8cE4XbzEHGth-Q/joinWe find the trigonometric Fo...as in Fig .4, the Fourier series on the interval (-2, 2) is : f HxL=1 - (13) 8 p2 B S n=1,3,5 ¶ cos In px 2 M n2 F Not surprisingly, the even extension of the function into the left half plane produces a Fourier series that consists of only cos (even) terms. The graph of this series is:-6 -4 -2 2 4 6 0.5 1.0 1.5 2.0 Fig. 6. Fourier series of y ...Let f be expressed by a half-range Fourier sine series : f ( x) ∼ ∑ n = 1 ∞ b n sin n π x λ. where for all n ∈ Z > 0 : b n = 2 λ ∫ 0 λ cos x sin n π x λ d x. In this context, λ = π and so this can be expressed more simply as: f ( x) ∼ ∑ n = 1 ∞ b n sin n x. where for all n ∈ Z > 0 : b n = 2 π ∫ 0 π cos x sin n x d ...ELG 3120 Signals and Systems Chapter 3 5/3 Yao ∑ ∑ +∞ =−∞ +∞ =−∞ = = k jk T t k k jk t x t a k e a e w0 (2p /), (3.20) is also periodic with period of T. • k = 0 , x(t) is a constant. • k = +1 and k = −1 , both have fundamental frequency equal tow 0 and are collectively referred to as the fundamental components or the first harmonic components.A periodic function f (t), with a period of 2π, is represented as its Fourier series,f ( t) = a 0 + Σ n = 1 ∞ a n cos n t + Σ n = 1 ∞ b n sin n tIff ( t) = { A sin t, 0 ≤ t ≤ π 0, π < t < 2 π ,the Fourier series coefficients a 1 and b 1 of f (t) are. A periodic function f (t), with a period of 2π, is represented as its Fourier ...Number Series. Power Series. Taylor / Laurent / Puiseux Series. Math24.pro [email protected] Free Fourier Series calculator - Find the Fourier series of functions Online.Fullscreen. This Demonstration shows how a Fourier series of sine terms can approximate discontinuous periodic functions well, even with only a few terms in the series. Use the sliders to set the number of terms to a power of 2 and to set the frequency of the wave. Contributed by: David von Seggern (University Nevada-Reno) (March 2011)Fourier Series Calculator is a Fourier Series on line utility, simply enter your function if piecewise, introduces each of the parts and calculates the Fourier coefficients may also represent up to 20 coefficients. Derivative numerical and analytical calculator8 Sep 2011 ... velocity:=piecewise(t<=6, 3*sin(t*Pi/6), t>6, 0);. How can I change this to a fourier series in a simple manner. Thanks for your advice.Fourier Transforms with the Ti-Nspire CX CAS; Math Calculator with Steps; TI-Calculator Shop: Find the Lowest Prices for TI-Calculators (with Price Comparison & Alerts) Best Uses of Log Graphing Calculator; Guest Posts are WelcomeSearching for Fourier Series Calculator? At mirmgate.com.au we have compiled links to many different calculators, including Fourier Series Calculator you need. Check out the links below. ... Wolfram|Alpha Widgets: "Fourier Series of Piecewise Functions" - Free Mathematics Widget Fourier Series of Piecewise Functions Fourier Series of Piecewise ...A question and an answer about how to compute the Fourier series of a piecewise function using a standard formula. The answer explains the interval of integral and the Fourier series of f f.$\begingroup$ @ErikVesterlund there are different definitions for the integral used to obtain the Fourier coefficients. In signal processing vs. say control vs. pure math. Different books use different definitions. So, if you are trying to compare results with some book, you need to make sure the same definitions are used in your code, else you'd think M is making a mistake.Fourier Series--Triangle Wave. Consider a symmetric triangle wave of period . Since the function is odd , Now consider the asymmetric triangle wave pinned an -distance which is ( )th of the distance . The displacement as a function of is then. Taking gives the same Fourier series as before.n’s are given by the Euler-Fourier formulas (8) and (9). For x= L, the series converges to 1 2 [f( L+) + f(L )]. In other words, when fand f0are piecewise continuous on [ L;L], the Fourier series converges to f(x) whenever fis continuous at xand converges to the average of the left- and right-hand limits at points where fis discontinuous ...are piecewise continuous on , then the Fourier series (7) is convergent. The sum of the Fourier series is equal to at all numbers where is continu-ous. At the numbers where is discontinuous, the sum of the Fourier series is the average of the right and left limits, that isto know under which conditions one can di erentiate or integrate the Fourier series of a function. The following theorems give these necessary conditions, which we state for 2l-periodic functions. It is obvious how the statements will change for the sine and cosine series. Theorem 5.6 (Integration of Fourier series). Suppose f is a piecewise ...Math 54: Fourier cosine and sine series May 1 Suppose that f is a (piecewise continuous) function on [0,L]. This is different from the setting of the ordinary Fourier series, in which we con-sidered functions on [L,L]. The Fourier cosine series represents f as asumoftheevenFouriermodes,i.e., f(x)= a 0 2 + X1 n=1 a n cos ⇣n⇡x L ⌘, where a ...How do you actually compute a Fourier Series? In this video I walk through all the big formulas needed to compute the coefficients in a Fourier Series. First...Best & Easiest Videos Lectures covering all Most Important Questions on Engineering Mathematics for 50+ UniversitiesTo Learn Basics of Integration … Watch th...where a 0 models a constant (intercept) term in the data and is associated with the i = 0 cosine term, w is the fundamental frequency of the signal, and n is the number of terms (harmonics). Curve Fitting Toolbox supports Fourier series regression for 1 ≤ n ≤ 8. For more information about Fourier series, refer to Fourier Analysis and Filtering.it means the integral will have value 0. (See Properties of Sine and Cosine Graphs .) So for the Fourier Series for an even function, the coefficient bn has zero value: \displaystyle {b}_ { {n}}= {0} bn = 0. So we only need to calculate a0 and an when finding the Fourier Series expansion for an even function \displaystyle f { {\left ( {t}\right ...Fourier Series 10.1 Periodic Functions and Orthogonality Relations The differential equation y′′ + 2y =F cos!t models a mass-spring system with natural frequency with a pure cosine forcing function of frequency !. If 2 ∕= !2 a particular solution is easily found by undetermined coefficients (or by using Laplace transforms) to be yp = F 2 ...Goffman, Casper. Everywhere convergence of Fourier series. Indiana Univ. Math. J. 20 (1970/71), 107-112. From the Math Review: The author obtains results on the everywhere convergence of the Fourier series of regulated functions that satisfy certain generalized conditions of bounded variation. (Regulated functions are those for which right and left limits exist at every point.)This apps allows the user to define a piecewise function, calculate the coefficients for the trigonometric Fourier series expansion, and plot the approximation. Cite As Mauricio Martinez-Garcia (2023).Fullscreen. This Demonstration shows how a Fourier series of sine terms can approximate discontinuous periodic functions well, even with only a few terms in the series. Use the sliders to set the number of terms to a power of 2 and to set the frequency of the wave. Contributed by: David von Seggern (University Nevada-Reno) (March 2011)Explore math with our beautiful, free online graphing calculator. Graph functions, plot points, visualize algebraic equations, add sliders, animate graphs, and more. Fourier Series | Desmos Loading... When dealing with Fourier cosine and sine series, you are actually extending a non-periodic function onto a periodic even or odd domain. Hence the effective period is actually twice as large instead, that is to say, you are actually working with the interval -4 < x < 4 here as the basic unit. Jan 2, 2015. #3.This worksheet will help with Piecewise functions. In order to change the graph, you NEED to input it in this format: if [x < #, first equation, second equation] You can change the #, first equation, and second equation for g (x). You can also change the #'s and the three equations for f (x). The format for graphing Piecewise Functions uses an ...Free functions and line calculator - analyze and graph line equations and functions step-by-step ... Integrals Integral Applications Integral Approximation Series ODE Multivariable Calculus Laplace Transform Taylor/Maclaurin Series Fourier Series Fourier Transform. Functions. ... Piecewise Functions; Continuity; Discontinuity; Values Table ...Step by step implementation of Fourier Series with MATLAB with downloadable code at https://angoratutor.com/fourier-series-magic-with-matlab. I start from de...How to calculate the Fourier cosine series of the periodic triangle function. Join me on Coursera:Matrix Algebra for Engineers: https://www.coursera.org/lea...The corresponding self-adjoint version of Bessel's equation is easily found to be (with Rj(ρ) = Jν(αjρ)) (ρR′j)′ + (α2jρ − ν2 ρ)Rj = 0. but we shall also need the values when i = j! Let us use the self-adjoint form of the equation, and multiply with 2ρR′, and integrate over ρ from 0 to c,Fourier Series is a way of approximating arbitrary function (f (x)) as an infinite sum of sines and cosines of increasingly high frequency that provide an orthogonal basis for the space of solution functions. The sine and cosine functions present as eigenfunctions of the heat equation. The specific frequencies provided present as eigenvalues ...Combining this with the fact that the Fourier series of f f on , fourier-series; piecewise-continuity; Share. Cite. Follow edit, If the function is periodic, then the behavior of the function in that interval allows us to find, About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Saf, If the function is periodic, then the behavior of the function in that interval allows us to find , Download the free PDF http://tinyurl.com/EngMathYTHow to compute Fourier series of odd and even functions. , A trigonometric polynomial is equal to its own fourier expansi, Fourier Series Calculator Piecewise . Let's define a f, A plot of this function is in Figure 9.3.1 for Ω = 4. For large Ω, Compute answers using Wolfram's breakthrough technology &, Free piecewise functions calculator - explore piecewise fun, First, the Fourier series of a function involves t, fourier series calculator. Version 1.0.0.0 (3.23 KB) b, a square wave = sin (x) + sin (3x)/3 + sin (5x)/5 + .., Example 6.3.5. The function f(t) = 3√t is not piecewise smooth, Find the Fourier series of the function and its sum fun, Compute the Fourier series of piecewise functions. Ge, Fourier Sine Series: bn = [2/ (n*pi)]* [ (-1)^ (n+1) + cos ( (n*pi).